Solar Warranties Explained: Product, Performance, Inverter & Workmanship
Straight answer: a solar system isn't covered by one warranty — it's four separate ones. The panels carry a product warranty (defects) and a performance warranty (output as they age); the inverter has its own; and your installer backs the workmanship — the install itself. Each has a different length and a different company standing behind it. Here's what each covers and who to call.
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- A solar system carries four warranties: panel product (defects), panel performance (output over time), the inverter, and your installer's workmanship. Add a battery and it brings its own.
- Manufacturers honor the equipment warranties (panels, inverter, battery); your installer honors the workmanship — so a workmanship warranty is only as good as the company still being in business.
- Typical lengths on premium gear: ~25 years product & performance on panels, ~25 years for microinverters (~12 years for string inverters, often extendable), and 10–15 years on batteries — but exact terms vary by manufacturer and contract.
A solar system isn't one warranty — it's four
When a proposal says "25-year warranty," ask which one. A rooftop system is really several products from several companies — panels, an inverter, racking, sometimes a battery — plus the labor that ties them to your roof. Each piece is covered by a different warranty, for a different length of time, honored by a different company. Here are the four (five with a battery), side by side.
| Warranty | What it covers | Typical length | Who honors it | What voids it |
|---|---|---|---|---|
| Panel product (materials) | Defects in the panel itself — cells, frame, glass, junction box, delamination | ~25 yr on many premium lines (10–12 yr on value panels) | Panel manufacturer | Unlicensed / DIY install, unauthorized repair, physical abuse |
| Panel performance (output) | A guaranteed minimum power output as the panel slowly degrades | ~25 yr, ending around 85–92% of original output | Panel manufacturer | Same as product; tampering or non-approved parts |
| Inverter | The inverter (and optimizers) that convert panel DC into home AC | Microinverter ~25 yr; string ~12 yr, often extendable | Inverter manufacturer | Unapproved install, unauthorized service, abuse outside spec |
| Installer workmanship (labor) | The install itself — mounting, flashing, roof penetrations, wiring, and the labor to swap a part | Varies widely — roughly 2–10 yr is common, some 10, 12, or 25 | Your installer | Third-party tampering — and it's only real if the installer is still in business |
| Battery (if added) | The storage unit — defects plus a guaranteed retained capacity | ~10–15 yr plus a throughput/cycle cap, ~70% capacity retained | Battery manufacturer | Unauthorized service; for some brands, long loss of internet |
Typical terms per EnergySage, SolarReviews, and manufacturer warranty documents. Exact coverage varies by manufacturer, model, and contract — always read the actual warranty.
1. Panel product (materials) warranty
This is the one most people picture: it covers the panel breaking or failing — manufacturing defects, a cracked cell, a bad junction box, frame corrosion, or delamination. If a panel fails from a covered defect, the manufacturer repairs it, replaces it, or provides a comparable or refurbished unit or a prorated credit — per the written terms.
Historically this ran 10–12 years, but most reputable residential brands now put 25 years on materials, and a few premium lines go further. It's honored by the panel maker, not your installer — though the installer usually files the claim and does the physical swap (which is where their workmanship warranty comes back in). Which brands carry the strongest coverage is its own question; we compare current models in best solar panels for California homes.
2. Panel performance (output) warranty
A panel can work perfectly and still make less power every year. The performance warranty guarantees a minimum output as it ages — a floor, not a promise of full output.
Most premium panels are warranted for about 25 years, ending somewhere around 85–92% of original output depending on the brand (better panels degrade slower and guarantee a higher year-25 number). This is separate from the product warranty: a panel can reach its output floor without ever "failing." We walk through exactly how the year-by-year math works — the small first-year drop, then roughly 0.3–0.5% a year — in solar panel degradation over time.
3. Inverter warranty
The inverter is the component most likely to need replacement at least once over the system's life — it does the most work. Its warranty is honored by the inverter manufacturer, and the length depends heavily on the type.
Microinverters (one small unit per panel) commonly carry about a 25-year warranty. A string inverter (one central box) is typically ~12 years, though many brands let you buy an extension to 20 or 25 years — usually within a window after purchase, for a one-time fee. Some optimizer-based systems split the difference: a shorter term on the inverter but a longer one on the per-panel optimizers. Terms vary by manufacturer and model, so confirm the number on your specific inverter. For how the two architectures actually differ, see Enphase vs SolarEdge.
4. Installer workmanship (labor) warranty
This is the one buyers overlook — and the one with the widest range. It covers the installation itself: how the panels are mounted, how the roof penetrations are flashed and sealed, the wiring, and the labor to pull and re-install a panel when a manufacturer part fails.
Here's the gap that catches people: a panel or inverter warranty covers the part, but not always the labor and roofing work to swap it, or a roof leak caused by a poor install. That's the workmanship warranty's job — and unlike the equipment warranties, it's backed by your installer, not a manufacturer. Length varies widely: roughly 2–10 years is common, and some companies offer 10, 12, or even 25. A longer number is only meaningful if the company is still around to honor it — which is why vetting the installer matters as much as the warranty length. Our guide to choosing a solar installer covers how to check that.
A workmanship warranty is only as good as the company behind it
Manufacturer warranties follow the equipment — if the panel brand still exists, the panel is covered no matter who installed it. A workmanship warranty follows the installer. If that company folds, merges, or was a fly-by-night reseller, a "25-year" labor warranty can quietly evaporate. So weigh a workmanship warranty alongside the installer's track record, licensing, and whether crews are in-house or subcontracted — not just the number on the page.
What voids a solar warranty
Warranties come with conditions. The most common ways homeowners lose coverage:
Unlicensed or DIY install
Most manufacturers require installation by a licensed contractor. A self-install or an unlicensed crew can jeopardize the equipment warranty from day one — though remedies and exclusions vary by manufacturer, so read the written terms.
Unauthorized repairs
Swapping a microinverter or opening a battery yourself — even with the right part — can void coverage on the surrounding equipment. Claims run through the manufacturer's process.
Non-approved parts
Off-brand clamps, wrong torque, mismatched breakers, or hardware not in the approved design can be grounds to deny a claim.
Physical abuse & neglect
Damage from misuse, unpermitted modifications, or failure to maintain the system as specified typically isn't covered.
Lost connection (some batteries)
A few battery brands require the unit to stay online for firmware updates; a long-term loss of internet can shorten the term. Check your battery's fine print.
A missed transfer
Warranties usually transfer to a new homeowner, but some require paperwork within a set window (and sometimes a fee). Miss it and coverage can lapse at sale.
Battery warranties: years, throughput, and retained capacity
If you add storage, its warranty works differently from a panel's. A battery wears with use, so its warranty is usually a three-part promise — and it ends whenever the first limit is reached.
Those three parts are: a time limit (commonly 10–15 years), a throughput or cycle cap (a total amount of energy you can push through it, often stated in MWh or a cycle count), and a retained-capacity guarantee (typically around 70% of original capacity remaining at the end of the term). For example, one widely used battery is warranted for 10 years with essentially no throughput cap for normal home use, while another guarantees 15 years or a set MWh throughput, whichever comes first — both promising roughly 70% capacity at the end. The exact numbers vary by manufacturer and model, so compare all three limits, not just the headline year count. We line up the leading options in Powerwall vs Enphase vs FranklinWH.
One licensed contractor behind the workmanship
Cali Energy installs in-house rather than handing your roof to a subcontractor, so the workmanship warranty is backed by the same licensed contractor that did the work (CSLB #1032379). The panel, inverter, and battery warranties are still honored by their manufacturers — that doesn't change — but when a part needs swapping, there's one company to call for the labor and the roof, not a chain of resellers. Ask us to walk through every warranty on any proposal, ours or a competitor's.
Check your proposal’s warranties for completeness
A warranty is only as good as its details. Enter the terms from a proposal and tick the coverage points it actually spells out. The tool scores completeness — not just years — and lists what to ask about. It reads the proposal, not the fine print of every manufacturer, so confirm the written warranty for remedies, exclusions and transfer rules.
Warranty completeness checklist
Enter each term (0 if not listed) and tick what the proposal spells out.
Benchmarks are common market examples (product ~25 yr, performance ~25 yr, inverter ~12–25 yr, workmanship ~10 yr), not a legal standard. A remedy may be repair, replacement, a refurbished unit or a prorated credit, and labor/freight can be excluded — the written warranty governs.
How to read the warranty section of a proposal
You don't need to assume anyone is hiding something — you just need each warranty stated plainly. A transparent proposal names, for every layer, the length and who honors it.
Look for four (or five) separate lines: panel product years, panel performance percentage at year 25, inverter years (and whether an extension is included or extra), workmanship years, and — if quoted — the battery's three limits. If any line is missing, blank, or lumped into a vague "25-year warranty," that's worth an itemized explanation before you sign — not proof of anything by itself. Also confirm the terms are transferable if you might sell. It's the same paperwork every reputable installer can produce, so a clear warranty table is simply easier to compare.
Get a proposal with every warranty spelled outFrequently asked
How many warranties does a solar system actually have?
Four, plus one if you add a battery. The panels carry a product warranty (defects) and a separate performance warranty (guaranteed output as they age); the inverter has its own; and your installer provides a workmanship warranty on the install itself. A battery adds a fifth. Each has its own length and its own company behind it.
What's the difference between a product and a performance warranty?
The product warranty covers the panel physically failing from a covered manufacturing defect — delamination, a defective cell, a bad junction box (impact, hail, transport, walking on panels, or improper install may be excluded). The performance warranty covers power loss over time, guaranteeing a minimum output (often around 85–92% of original at year 25). A panel can reach its output floor without ever "failing," so the two protect against different problems. Both are honored by the panel manufacturer.
How long is a solar inverter warranty?
Microinverters typically carry about 25 years. A string inverter is usually ~12 years, though many manufacturers let you extend it to 20 or 25 for a one-time fee, usually within a window after purchase. Since the inverter is the part most likely to need replacing, it's worth confirming the exact term — and whether any extension is included — on your specific model.
What voids a solar panel warranty?
It depends on the written warranty, but common triggers include unauthorized repairs or modifications and non-approved parts (off-brand clamps, mismatched hardware). Some manufacturers may also exclude coverage for a self-install, an unlicensed install, physical abuse, unpermitted changes, or skipped maintenance — the exact exclusions vary by brand, so read the specific model's warranty. Manufacturer claims run through an approved process, which is one reason DIY fixes are risky.
Are solar warranties transferable if I sell my house?
Often, but it depends on the written warranty. Some transfer automatically; others require the buyer to submit a transfer notice within a set window (30–90 days is common) and sometimes a small fee, and a few are limited to the original owner. Confirm the transfer rules for each warranty (panels, inverter, battery, workmanship) before closing so coverage doesn't lapse.
If the panels are warrantied for 25 years, why does the workmanship warranty matter?
Because the manufacturer covers the part, not always the labor to remove and reinstall it — or a roof leak caused by a bad install. That's the workmanship warranty's job, and it's backed by your installer, not the panel maker. A long equipment warranty doesn't help much if no one will do the labor, which is why the installer's longevity matters.
Related reading
Know who stands behind every warranty on your system
Cali Energy installs in-house and backs the workmanship ourselves — one licensed contractor to call (CSLB #1032379), plus the manufacturer warranties on your panels, inverter, and battery. Ask us to walk through every line before you sign.
Get a free estimatePrepared by Cali Energy, July 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)